Design rules commonly govern the manufacture of macrocells and standard cells, either of which form a portion of a customizable logic array structure or the like. For example, most manufacturing processes require a minimum separation distance between conductors, such as traces and vias. To maintain a minimum separation distance, traces are usually routed along a grid, which is also known as a “routing grid.” Vias are also typically formed upon the grid. Further, manufacturing processes require a minimum amount of area to cover or overlap vias. As such, vias have dimensions that typically extend beyond the width of a trace. So by placing vias on a grid, the minimum separation distance increases to accommodate the vias. This, in turn, decreases routing density.
FIG. 1A is a diagram showing a traditional routing grid 100 composed of vertical grid lines 110 and horizontal grid lines 120 that are spaced apart by a vertical grid spacing (“g.s.(v)”) 111 and a horizontal grid spacing (“g.s.(h)”) 113, respectively. Via cap 102 includes an area, A, that is sufficient to cover a via to meet a minimum amount of coverage area. Further, via cap 102 is positioned a minimum separation distance (“d”) 115 from any of the grid lines over which another via or trace can be disposed. But vertical grid spacing 111 and horizontal grid spacing 113 can contribute to a reduced routing density.
FIG. 1B is a diagram showing an improved routing grid 150 designed to reducing at least one of the spacings between the grids. Improved routing grid 150 has vertical grid lines 160 and horizontal grid lines 170, which are spaced apart by vertical grid spacing (“g.s.(v)”) 151 and horizontal grid spacing (“g.s.(h)”) 153, respectively. Here, Via cap 102 vertical grid spacing (“g.s.(v)”) 151 is reduced in comparison vertical grid spacing 111 of FIG. 1A to improve routing density. To satisfy the requirement to cover vias (not shown) with via cap 152 having at least a minimum amount of area, A, via cap 152 is extended in a direction so as to maintain distance (“d”) 115. Consequently, horizontal grid lines 170a, which are shown as dashed lines, are typically removed to accommodate the extended vertical dimension of via cap 152 that is necessary to comply with design rules. This increases horizontal grid spacing 153 Further, via cap 102 is positioned a minimum separation distance (“d”) 115 from any of the grid lines over which another via or trace can be disposed. But vertical grid spacing 111 and horizontal grid spacing 113 can contribute to a reduced routing density, especially when routing grid 150 is used for manufacturing multiple layers.
In view of the foregoing, it would be desirable to provide cells, methods and computer readable media that minimize the above-mentioned drawbacks and provide for a modified routing grid and an extended via cap to enhance routing density.